Native Forest Soils Holds More Carbon Than Trees. But Lockouts Burn Both

Why It Matters

Recognizing soil as the primary carbon reservoir reshapes forest management and climate policy, offering a more effective pathway to reduce emissions and wildfire risk in Australia.

Key Takeaways

• Soil stores more carbon than above‑ground forest biomass in Australia.
• Indigenous cultural burns create grass‑understory, enhancing soil organic matter.
• Dense, unmanaged forests increase fire risk by drying soils and air.
• Managed thinning with grass layers improves water retention and reduces fuel loads.
• Policy shift toward soil‑focused regulation could boost climate mitigation.

Pulse Analysis

Recent scientific work by soil chemist Phil Mulvey and communicator Freya Mulvey reinforces a growing consensus that terrestrial soils hold the majority of terrestrial carbon, often exceeding the storage capacity of forest canopies. In Australian eucalypt landscapes, deep organic‑rich topsoil can contain up to twice the carbon found in the standing timber. This hidden reservoir also regulates heat exchange and moisture fluxes, meaning that soil degradation not only releases CO₂ but also intensifies local temperatures and reduces rainfall. Understanding these dynamics is essential for any realistic national emissions inventory.

Aboriginal fire stewardship provides a practical blueprint for leveraging that soil potential. Controlled, low‑intensity burns maintain an open woodland structure where grasses and forbs coexist with scattered trees, fostering a thick organic layer that improves aeration, water infiltration, and fungal networks. Research cited by the Mulveys shows that such cultural burns keep fire fronts above moist topsoil, raising relative humidity and curtailing flame spread. Historical accounts, from early European explorers to recent fire events, confirm that landscapes managed with regular cultural burning experience fewer crown‑fire incidents and retain higher soil carbon stocks.

Translating these insights into policy could reshape Australia’s climate strategy. By shifting emphasis from preserving untouched timber to enhancing soil health through managed thinning, grass‑understory restoration, and support for Indigenous fire practices, governments can unlock a larger, more resilient carbon sink while reducing wildfire severity. Economic analyses suggest that every dollar invested in soil‑focused management yields multiple dollars in avoided fire suppression costs and carbon credits. Embedding soil security into national land‑use legislation therefore offers a pragmatic, cost‑effective lever for meeting emission targets.